A top U.S. military official confirmed Wednesday that Russia has deployed a new type of cruise missile that violates a longstanding arms control accord.

The Trump administration is looking to respond, he said. And Congress wants to know how.

At a House Armed Services hearing, Air Force Gen. Paul Selva, vice chairman of the Joint Chiefs of Staff, seemed to have been the first American official to say on the record that the missiles are now operational, a fact reported last month by The New York Times. Selva did not say the name of the new type of nuclear-capable missile, the SSC-8, nor did he say where they are located, which is believed to be on Russian territory.

Ground-launched missiles of a certain range — such as the SSC-8, which can reportedly fly up to 3,400 miles — are banned under the Intermediate-Range Nuclear Forces Treaty, known as INF, which the United States and Russia signed in 1987.

“We believe that the Russians have deployed a land-based cruise missile that violates the spirit and intent of the Intermediate Nuclear Forces Treaty,” Selva said, adding that he did not expect Russia to reverse course.

The nuclear posture review that Trump required in a January executive order would include a “set of options” for countering Russia’s deployment, Selva also disclosed.

Rogers wants answers

Alabama Republican Mike D. Rogers, who chairs the House Armed Services subcommittee on strategic forces, asked at the hearing that Selva and another Air Force four-star general, John Hyten, chief of U.S. Strategic Command, provide lawmakers with response options by the end of the month.

“To hear the vice chairman of the Joint Chiefs of Staff confirm that Russia has now deployed its INF Treaty-violating missile and that he doesn’t believe they intend to return to the treaty is an alarming, but not surprising, statement,” said Rogers in a written response to a query from CQ Roll Call. “That is why I asked Gen. Selva and Gen. Hyten for a set of military response options by the end of this month — which they agreed to do. Russia’s actions are an undeniable threat to our security.”

President Donald Trump told Reuters last month he would raise the cruise missile development with Russian President Vladimir Putin “if and when we meet.”

The U.S. responses could include deployment of offensive missiles or additional anti-missile capabilities in Europe. Whatever counterpunches the Trump administration throws will have ramifications for global security. The consequences will be felt most immediately in Europe. But the U.S. military, if unconstrained by the INF Treaty, might also deploy new types of ground-based intermediate range missiles in Asia, too, which also could trigger responses by North Korea or China.

To many hawks in Congress, however, the risks of not responding to a blatant treaty violation outweigh any perils associated with new U.S. military moves.

Arms control worries

Arms control advocates, by contrast, say that while Russia’s violation of the INF treaty is regrettable, they also worry that Trump might respond by deploying comparable weapons overseas. NATO may split over doing so in Europe, they say. Russia is also looking to build and field more intermediate range missiles, not just in Europe, they say, so a new cycle of missile escalation could follow. Other arms control agreements could disintegrate if the INF Treaty falls, they add.

“That is the wrong response because we’d give the Russians a cynical excuse to continue their current course and we’d shift the blame away from Russia for violating this treaty and to the U.S.,” said Daryl G. Kimball, executive director of the Arms Control Association, in an interview Wednesday.

Trump’s response to Moscow’s moves will occur against a backdrop of charged questions concerning how the new president will handle an assertive Russia. Trump, like his two immediate predecessors, has said he wants cooperation with Moscow. But Putin may have other ideas. Trump is under pressure, too, not to be too conciliatory toward Putin. Complicating matters further, there are now signs Russia is not so sure it can get along well with Trump after all.

Escalation fears

U.S. officials first became aware that Russia was testing SSC-8s in 2008. The State Department in 2014 first publicly accused Russia of violating the INF Treaty.

SSC-8 missiles are not only capable of delivering nuclear warheads across several thousand miles but, more disturbingly, they are road-mobile and therefore easily hidden.

“The system itself presents a risk to most of our facilities in Europe,” Selva said. “We believe that the Russians have deliberately deployed it in order to pose a threat to NATO and to facilities within the NATO area of responsibility.”

Massachusetts Democrat Seth Moulton, a member of House Armed Services, said at the hearing that the Russian cruise missile deployment “is part of a broader move of Russian aggression throughout Europe and against NATO.” However, he added, he’s also concerned about how both sides act, and worries “that a conventional conflict could escalate to the point where it becomes nuclear.”